QCE Digital Solutions Unit 4 Word Scramble: Digital Methods for Exchanging Data (Modules 17–88)
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Word scramble
Unscramble the letters and write each key term on the line.
1
OFGDENRSL HRCIPE
A Vigenere variant whose key is a string of digits 0-9, like 31415. Each digit is the shift for one letter, and the key repeats along the message.
2
TEM-NOEI APD
Encryption using a truly random key as long as the message, used only once. Never reused, it is unbreakable in theory, but the pad must be shared securely.
3
KCOLB REIHPC
Encrypts data in fixed-size blocks (e.g. 128 bits) using a key, scrambling each block in rounds. A longer key means more possible keys, so brute force takes longer.
4
SED
Data Encryption Standard: an early symmetric block cipher using 64-bit blocks and a 56-bit key. Now insecure because modern computers can brute-force its small key.
5
RTILPE SED
Applies DES three times (encrypt, decrypt, encrypt) with two or three keys to lengthen the effective key and strengthen DES. It is slower than AES.
6
HWFLOSIB
A fast symmetric block cipher with a variable-length key (up to 448 bits) and 64-bit blocks. It is free for anyone to use, as it is in the public domain.
7
OTISWFH
A symmetric block cipher and Blowfish's successor. It encrypts 128-bit blocks with keys up to 256 bits and was a finalist in the competition that chose AES.
8
SMPRCOSE ENTH YRTPCNE
Compress first, then encrypt, and hash to check integrity. Encrypted data looks random so it cannot be compressed. On receiving, reverse the order: decrypt, then decompress.
9
RJEITT
The variation in latency between packets, so they arrive at uneven intervals. Measured in milliseconds, it disrupts voice and video unless a ______ buffer smooths it.
10
AATUEDGREN VYEILEDR
Every packet is confirmed as received (acknowledged). Missing or damaged packets are resent so no data is lost, but waiting and resending adds extra delay.
Answer Key
QCE Digital Solutions Unit 4 · Modules 17–88
1OFGDENRSL HRCIPE → Gronsfeld cipher — A Vigenere variant whose key is a string of digits 0-9, like 31415. Each digit is the shift for one letter, and the key repeats along the message.
2TEM-NOEI APD → one-time pad — Encryption using a truly random key as long as the message, used only once. Never reused, it is unbreakable in theory, but the pad must be shared securely.
3KCOLB REIHPC → block cipher — Encrypts data in fixed-size blocks (e.g. 128 bits) using a key, scrambling each block in rounds. A longer key means more possible keys, so brute force takes longer.
4SED → DES — Data Encryption Standard: an early symmetric block cipher using 64-bit blocks and a 56-bit key. Now insecure because modern computers can brute-force its small key.
5RTILPE SED → Triple DES — Applies DES three times (encrypt, decrypt, encrypt) with two or three keys to lengthen the effective key and strengthen DES. It is slower than AES.
6HWFLOSIB → Blowfish — A fast symmetric block cipher with a variable-length key (up to 448 bits) and 64-bit blocks. It is free for anyone to use, as it is in the public domain.
7OTISWFH → Twofish — A symmetric block cipher and Blowfish's successor. It encrypts 128-bit blocks with keys up to 256 bits and was a finalist in the competition that chose AES.
8SMPRCOSE ENTH YRTPCNE → compress then encrypt — Compress first, then encrypt, and hash to check integrity. Encrypted data looks random so it cannot be compressed. On receiving, reverse the order: decrypt, then decompress.
9RJEITT → jitter — The variation in latency between packets, so they arrive at uneven intervals. Measured in milliseconds, it disrupts voice and video unless a jitter buffer smooths it.
10AATUEDGREN VYEILEDR → guaranteed delivery — Every packet is confirmed as received (acknowledged). Missing or damaged packets are resent so no data is lost, but waiting and resending adds extra delay.